What is Mitochondrial Disease?

What is Mitochondrial Disease?

Marni Falk, MD: Welcome to Mito 101, your introduction to mitochondria, mitochondrial disease, how it's treated today and what's ahead. This presentation was developed by the mitochondrial medicine team at Children's Hospital of Philadelphia. I'm Dr. Marni Falk, Executive Director of the Mitochondrial Medicine Program.

Mitochondria are specialized compartments found in every one of your body's cells except mature red blood cells. Think of mitochondria as tiny but powerful batteries. Their job is to make the energy your cells need to survive. In fact, mitochondria are oxygen and calorie burning factories that produce more than 90% of your body's energy.

Mitochondria are especially important in organs that demand a lot of energy, like your heart, brain, liver and muscles. 40% of each heart cell and 25% of each liver cell are made of mitochondria. So they are essential to support many critical body functions. Mitochondria create more than 90% of the energy your body needs.

If we think of mitochondria as batteries of the cells in a very fit person, like an extreme athlete, the batteries are fully charged. For most of us, the batteries may not be as full, but there is still plenty of energy to function well, but when mitochondria fail, they produce less and less energy within cells, which can result in a range of acute or chronic disease symptoms.

Mitochondrial disease or dysfunction, as it's also called, happens when something causes a change in the mitochondria, so they can't produce enough energy for a cell or organ to function properly. Genetic based mitochondrial disease is chronic, meaning that its symptoms last over time. However, some people can be generally stable in their symptoms but experience acute exacerbations or decompensation at times of stress. We don't yet fully understand all possible causes of mitochondrial disease. However, we do know that there are many genetic disorders that directly disrupt mitochondrial function. Most mitochondrial disease is inherited by a person from a gene mutation or change in the mitochondrial DNA or in the nuclear DNA from one or both of their parents.

We now know that mitochondrial disease can result from mutations or changes in any of more than 350 different genes. For that reason, symptoms are often very different from person to person. Medical problems may range from fatigue and weakness, to irregular heartbeat, developmental disabilities, growth problems, metabolic stroke, seizures and many others. The average mitochondrial disease patient has 16 unique symptoms, which can make diagnosing a common root cause challenging. Mitochondrial disease is actually not that rare. Worldwide, it occurs in at least one in every 4,300 people. And it affects both children and adults.

Mitochondrial dysfunction may also occur in a host of other medical conditions as well as from medications or environmental exposures. Mitochondrial medicine is still a new field. The first mitochondrial DNA disease was only discovered in 1988 by Dr. Doug Wallace, who is now here at Children's Hospital of Philadelphia.

Since then we've learned much about mitochondria and their role in our cells and organs, but there's much more of the mystery yet to unravel. Currently there is no cure for mitochondrial disease. Because the disorder is different in each patient, personalized treatment is essential. Treatment can include medication or a combination of medications.

Exercise, nutrition programs and supplemental therapies can also play an important role in treatment. At Children's Hospital, mitochondrial medicine patients are cared for by an entire team of experts, including a suite of primary mito docs and diverse specialty physicians, genetic counselors, a nurse practitioner, nurses, a dietician, a social worker, patient navigators, physical therapists and an exercise physiologist. Together, we create an individualized care plan that can be quite successful to stabilize and optimize each patient's health and functioning. At CHOP, our team is dedicated to solving the mysteries of mitochondrial disease. We are focused on translational research, taking patient questions to the research lab and then applying what we learn in the research lab to directly improve care for patients. We're also working to identify connections between mitochondrial disease and other conditions like Alzheimer's disease, Parkinson's disease, diabetes, aging, and cancer. Because mitochondria plays such a vital role in our cells and organs, treatments for mitochondrial disease may ultimately improve treatments for the other more common diseases and vice versa.

There are a number of different tests that help us diagnose mitochondrial disease and many of them were developed by the CHOP team. We are currently working on even more precise, noninvasive testing methods, such as a test in which patients briefly exercise inside an MRI scanner, allowing us to directly measure their mitochondrial function.

All of this learning helps us find better, more personalized ways to treat mitochondrial disease. You can learn more about mitochondrial medicine at Children's Hospital of Philadelphia. Call or email for an appointment or visit our website, chop.edu/mito.